Dealing with potential TEST_METADATA and atf_set duplication

[Garrett Cooper]

Hello again Julio!
    I'm adding testcases that require root and I was wondering:
    1. Should I add TEST_METADATA.test_app+= require.user="root" to
the Makefile, which puts the necessary lua magic in the Kyuafile?
    2. Should I add atf_set "required.user" "root" -- or
atf_tc_set_md_var("require.user", "root") -- in the testcase header?
    3. Should I add both items?
    There are test engineers that run testcases without isolation,
e.g. /path/to/test_app testcase_name -- should we support this
workflow, or not?
Thanks!
-Garrett